1. The thickness of the heating resistor is uneven. Both the screen printing and sintering processes will affect the thickness uniformity of the thick film resistor. When the thick film is uneven, the resistance of the weak link is large, and the heat generation is also large, which is easy to form hot spots and eventually burn out.
2. The surface of the heating body is uneven and the temperature field is distributed unevenly. Usually, the wiring method on the surface of the thick monkey heating element and the structure of the product have a great influence on the distribution of the temperature field. When the temperature field is unevenly distributed, it is easy to cause the different expansion coefficients of the substrate and the heating wire to damage the circuit. The uniformity of the temperature field is one of the most important indicators when designing a thick waist heating element.
3. The temperature controller is not protected in time. When the appliance is in dry burning or other conditions that cause the temperature to rise abnormally, the heating element will be protected at 100°C per second or even in time, which will eventually lead to damage to the heating resistor. Therefore, the choice of the protector is very important for the life of the thick film heating element.
4. High power density or current density. Usually, the power or current density of the thick mold heating element must have enough margin, and the margin is insufficient, which will lead to the failure of the thick resistor under time accumulation or other abnormal conditions.
5. Substrate deformation. If the substrate material or structure design is unreasonable, or the substrate is deformed due to other structural reasons, the heating resistor attached to it will also undergo phase change and be damaged.
